When dancer-choreographer David Parsons began working with jazz pianist Billy Taylor, he learned one thing very quickly.

"Billy's not going to play the same way every night," Parsons said in a recent interview. That meant Parsons would have to adapt to at least some new music at every performance.

But that was part of the challenge, since the dancer wouldn't dream of asking Taylor to play the same thing night after night. "You don't do that with jazz musicians if you understand jazz," he said.

Parsons, 35, was speaking by phone recently from backstage at a theater in Muncie, Ind., one stop on a 12-city tour that includes shows tonight and Tuesday at the Irvine Barclay Theatre, where he and Taylor are presenting their collaborative "Step Into My Dream."

Parsons was one of the leading dancers in the Paul Taylor Dance Company for nine years before leaving in 1987 to form his own company. Billy Taylor, 72, has had an illustrious jazz career that has spanned half a century.

The two met several years ago while they were appearing separately in a summer festival in Tucson. "We had dinner together," Parsons said. "We liked each other." A mutual friend suggested they collaborate. "We said, 'Yeah!' "

Said Taylor: "I saw his work and really enjoyed it. It's very imaginative and different from most of the dance companies I had worked with. I was very excited about a collaboration. And it really was a collaboration."

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So much so that Taylor's trio--Taylor on piano, bassist Chip Jackson and drummer Steve Johns--appears onstage with the nine members of Parsons' company during "Step Into My Dream" on this tour, rather than remaining anonymously out of sight in the orchestra pit.

Taylor said he tried to give Parsons a broad range of musical moods to work with. "The things he did were so athletic, so different, I didn't really know what to write for him, so I wrote a wide variety of things," Taylor said. "I had kind of a story-line base--a walk down 125th Street (in Harlem), how it used to look and sound. I wrote about an hour's worth of music. I told David, 'You're free to take what you want, put it in any order you want.' "

Said Parsons: "He came up with some beautiful stuff. He goes through time. . . . He saw the past, the present and the future, how different clubs' music changed: Jazz through the ages, all the way up from blues and ragtime to rap."

But Parsons doesn't take the audience on exactly the same walk, according to Taylor.

"I wrote 'Kim's Song,' " he said. "He heard it as a very romantic song, choreographed it for two people. I had thought of it as a sort of promenade, with lots of people.

"Then 'Uncle Bob': For me what I had in mind, there was this nightclub, really just a little bar down from the Apollo (Theater) and a solo pianist who reminded me of my uncle who used to play this style, but this guy could really play this style. (So I wrote) a little ragtime piece. But (David) doesn't do a ragtime dance. He does a very eccentric, a little abstract dance."

"Billy gave me total leeway," Parsons said. "We tightened some things, lengthened some things, played with the order. It was wonderful what Billy did. He gave me a wide variety of music, all original, which I love in this world of things that are so meticulously controlled in videos or movies. It's great to have that freedom. Every night there's a difference in the performance. There's structure to it, but within that structure, (dancers and musicians) are improvising.

"Improvisation can be very indulgent, if you do it without a structure around it," he added. "But we've been working for four years now on improvisation, using different things--live radio, different music. It was all getting ready to work with Dr. Taylor."

In the middle of the piece, there is a section in which Parsons decides who is to dance only moments before the company goes on, he said.

"I can pick duets, trios or just single dancers. No one knows who's going to start. The only stipulation is that (the dancers) point to the musicians they want to use, whether just piano or just drums or both or whatever. You point to them. To start (the dance), you bow to them. To finish, you bow, to put a period on it.

"The inspiration goes back and forth. It's right there in front of you, then it's gone. It embodies my dancers' sensitivity and creativity they don't usually get to show."

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Taylor said that it's this middle section that varies the most. "It's literally different every time we do it because even if he picks the same dancers, they can chose different musicians," he said. "The music comes from the movement, the movement comes from the music.

"For me, it really is a stretch, and for the dancers also, I think. There is so much difference between a dancer dancing to a record or a tape and dancing to live music. There's an excitement that happens every time to all concerned. But there was never any part that we felt wasn't going to work. I had so much faith in David."

* The Parsons Dance Company will collaborate with the Billy Taylor Trio in "Step Into My Dream" tonight and Tuesday at the Irvine Barclay Theatre, 4242 Campus Drive in Irvine. The program also includes Parsons' "Nascimento" and "Caught," and Taylor originals and jazz standards. 8 p.m. $25. (714) 854-4646.